The invention is related to the art of network interworking. The invention will be described in terms of interworking between networks of the Global System for Mobile Communication (GSM) and (Telecommunications Industry Association) TIA-41 Mobile Application Part (MAP) protocols. However, the invention may be applicable in other interworking or message translation applications.
A number of mobile communication technologies exist. For example, a technology known as the Global System for Mobile Communication (GSM) is widely deployed in Europe. In North America, mobile networks implementing the TIA-41 protocol predominate. This development of multiple standards has led to certain inefficiencies. For example, electronic devices, such as cellular phones, laptop computers and personal digital assistants, must be designed and manufactured to communicate with networks based on one of the protocols. The market for such devices is reduced because customers served by another standard are removed as potential customers. Alternatively, the devices can be manufactured to communicate with two or more of the communication network protocols. However, this can adversely affect the development time, size and production costs of these devices.
This has led to efforts to unify communication networks, or at least provide means for interworking between networks. For example, the GSM/ANSI-136 Interoperability Team (GAIT) has promulgated standards for TIA-41-GSM interworking. The GAIT standards address roaming scenarios for mobile communications subscribers that allow the subscribers to move between GSM and TIA-41 networks. New Gateway devices including Interworking and Interoperability Functions (IIF) have been developed to provide for interworking between networks. However, the GAIT standards do not address the interworking problems that exist where an originating Mobile Switching Center (MSC) is in a different realm (TIA-41 vs. GSM MAP) from a subscriber's Home Location Register (HLR). There is no provision, for example, for allowing a TIA-41-based Mobile Switching Center (MSC) to communicate with a GSM-based HLR for the purposes of location query and call setup.
This deficit in Mobile Application Part (MAP) interworking makes it difficult for mobile communications service providers to use more than one technology in their networks. Therefore, there is desire for an Inter Technology Bridge (ITB) to interface messages between these disparate protocols.